The present invention relates to a microwave excitation plasma processing apparatus used for etching and ashing in the manufacture of a semiconductor device and the like, and a microwave excitation plasma processing method.
As a conventional microwave excitation plasma processing apparatus, one having a structure disclosed in Jpn. Pat. Appln. KOKAI Publication No. 61-131454 is known. This plasma processing apparatus has a vacuum container, a dielectric window, a waveguide, and a microwave oscillator. The vacuum container has a plasma generating chamber at its upper portion and a processing chamber which is formed under the plasma generating chamber and in which a processing target member is arranged. The dielectric window is arranged in the opening of the upper wall portion of the vacuum container. The waveguide is arranged on the upper wall portion of the vacuum container including the dielectric window. The microwave oscillator introduces a microwave into the waveguide. The waveguide has a rectangular shape. The waveguide has a first wall having a first surface opposing the dielectric window and perpendicular to the direction of electric field of the microwave, second walls having second surfaces extending perpendicularly to the first surface and parallel to the direction of electric field of the microwave, a third wall having a third surface (short-circuiting surface) which is provided on a side opposite to the microwave introducing side perpendicularly to the first and second surfaces to reflect the microwave. The opening portion is formed in an entire first wall portion of the waveguide that opposes the dielectric window. The microwave is introduced from the opening portion into the plasma generating chamber through the dielectric window.
In the microwave excitation plasma processing apparatus described above, since, the distribution of electric field in the plasma generating chamber varies to make the plasma nonuniform, etching and ashing by the plasma processing apparatus become nonuniform.